Undesired ice accumulation on infrastructure and transportation systems leads to catastrophic events and significant economic losses.Although various anti-icing surfaces with photothermal effects can initially prevent...Undesired ice accumulation on infrastructure and transportation systems leads to catastrophic events and significant economic losses.Although various anti-icing surfaces with photothermal effects can initially prevent icing,any thawy droplets remaining on the horizontal surface can quickly re-freezing once the light diminishes.To address these challenges,we have developed a self-draining slippery surface(SDSS)that enables the thawy droplets to self-remove on the horizontal surface,thereby facilitating real-time anti-icing with the aid of sunlight(100 m W cm^(-2)).This is achieved by sandwiching a thin pyroelectric layer between slippery surface and photothermal film.Due to the synergy between the photothermal and pyroelectric layers,the SDSS not only maintains a high surface temperature of 19.8±2.2℃at the low temperature(-20.0±1.0℃),but also generates amount of charge through thermoelectric coupling.Thus,as cold droplets dropped on the SDSS,electrostatic force pushes the droplets off the charged surface because of the charge transfer mechanism.Even if the surface freezes overnight,the ice can melt and drain off the SDSS within 10 min of exposure to sunlight at-20.0±1.0℃,leaving a clean surface.This work provides a new perspective on the anti-icing system in the real-world environments.展开更多
In order to alleviate the growing problem of electromagnetic radiation pollution,it is both urgent and challenging to develop electromagnetic wave absorbing materials with strong absorption and wide effective absorpti...In order to alleviate the growing problem of electromagnetic radiation pollution,it is both urgent and challenging to develop electromagnetic wave absorbing materials with strong absorption and wide effective absorption bandwidth(EAB).The structural design of heterojunction surfaces plays an important role in the development of advanced microwave absorbing materials.Building on this concept,three-dimensional nanocomposites Alk-Ti_(3)C_(2)T_(x)/nitro metal phthalocyanine(TNMP)with phthalocyanine derivative NMP-MXene are designed.TNMP composites are prepared by self-assembly of surface hydroxylated treated MXene with floral spherical nitrophthalocyanine.This method effectively constructs rich heterojunction surfaces and induces dipole polarization effect by designing a large number of oxygen vacancies through coordination,which effectively enhances the material attenuation capability while balancing impedance matching characteristics.By modulating the metal centers in the NMP,the coordination mode of the heterojunction surfaces is regulated,and the polarization relaxation loss is improved to achieve excellent electromagnetic wave absorption performance(reflection loss(RL)of-62.12 dB at a thickness of 1.25 mm).And based on the bionic structure design,a unit cycle structure of double-layered butterfly wing skeleton(DLBWS)is constructed to obtain an ultra-wideband electromagnetic wave absorber with an EAB of 12.5 GHz.This research demonstrates a regulatory scheme to elucidate the dipole polarization mechanism and proposes a new method for designing functional materials in ultra-broadband electromagnetic wave absorption.展开更多
The design and fabrication of efficient microwave absorbing materials with tunable wave attenuation capacity to address the increasing demand for electromagnetic pollution mitigators remains a challenging task.In this...The design and fabrication of efficient microwave absorbing materials with tunable wave attenuation capacity to address the increasing demand for electromagnetic pollution mitigators remains a challenging task.In this study,Ag_(2)Te and a series of Ag/Ag_(2)Te composites have been successfully synthesized by using a facile one-step solvothermal method through varying the molar ratio of the reactants and reaction time.To investigate the microwave absorption performance of these composites,the samples are mixed with polyvinylidene difluoride matrix under different filler ratios.The experimental results indicate that the AT3(where the molar ratio of Ag:Te is 4:1)sample possesses optimal wave dissipation ability with a minimum reflection loss value of−55.98 dB at 15.01 GHz and a maximum effective absorption bandwidth of 4.90 GHz(13.10-18.00 GHz)at a thickness of 1.7 mm when the filler content is 10 wt.%.Moreover,the widest EAB of 6.20 GHz(10.60-16.80 GHz)is recorded in the Ag_(2)Te sample.Meanwhile,it is observed the solvothermal reaction time can effectually influence effective wave absorption frequency.As the reaction time increases,the position of the minimum reflection loss(RLmin)shifts to lower frequencies.The analysis of the wave absorption mechanism demonstrates that the novel crooked one-dimensional linear structure and abundant heterogeneity within the Ag/Ag_(2)Te composite plays an important role in achieving outstanding wave absorption performance.The specific wave absorption mechanism includes conductive loss,multiple scattering,multiple resonant coupling,interface polarization and electric dipole polarization.This work can provide an effective strategy for the design of high-performance MAMs through constituent and morphology modulation.展开更多
Traditional cloth diapers are fully reliant on the water retention capacity of the absorbent cores to deter leaks,often overlooking the role of the top sheet,which can lead to reverse osmosis of absorbed urine.Janus m...Traditional cloth diapers are fully reliant on the water retention capacity of the absorbent cores to deter leaks,often overlooking the role of the top sheet,which can lead to reverse osmosis of absorbed urine.Janus membranes,known for their liquid diode effect,present an ideal material for the top sheet of cloth diapers.However,the widespread application of Janus membranes in cloth diapers faces challenges such as failure to meet anti-backflow requirements,limited biocompatibility,and insufficient antimicrobial properties.Here,a multifunctional Janus fabric for the top sheet of cloth diapers is developed through the synergistic combination of gradient wettability and nanoparticle functionality.The modulable gradient wettability provides unidirectional liquid transport with a high rectification ratio,which is essential for preventing liquid backflow.Consequently,prototype cloth diapers incorporating Janus fabrics as the top sheet outperform commercial products in wetback resistance.Functionalized silver nanoparticles not only provide the necessary micro-nano hierarchical structure for gradient wettability but also endow Janus fabrics with excellent chemical antibacterial properties.The integration of dryness derived from the excellent unidirectional transport performance and antibacterial properties effectively prevents bacterial growth on cloth diapers.Additionally,the Janus fabrics exhibit excellent washability and biocompatibility,further enhancing their potential applications in reusable cloth diapers.展开更多
基金supported by the National Natural Science Foundation of China(52273101,51922018,and 21875011)the Fundamental Research Funds for the Central Universities(KG21015201 and KG21020801)China Postdoctoral Science Foundation(2025M77422)。
文摘Undesired ice accumulation on infrastructure and transportation systems leads to catastrophic events and significant economic losses.Although various anti-icing surfaces with photothermal effects can initially prevent icing,any thawy droplets remaining on the horizontal surface can quickly re-freezing once the light diminishes.To address these challenges,we have developed a self-draining slippery surface(SDSS)that enables the thawy droplets to self-remove on the horizontal surface,thereby facilitating real-time anti-icing with the aid of sunlight(100 m W cm^(-2)).This is achieved by sandwiching a thin pyroelectric layer between slippery surface and photothermal film.Due to the synergy between the photothermal and pyroelectric layers,the SDSS not only maintains a high surface temperature of 19.8±2.2℃at the low temperature(-20.0±1.0℃),but also generates amount of charge through thermoelectric coupling.Thus,as cold droplets dropped on the SDSS,electrostatic force pushes the droplets off the charged surface because of the charge transfer mechanism.Even if the surface freezes overnight,the ice can melt and drain off the SDSS within 10 min of exposure to sunlight at-20.0±1.0℃,leaving a clean surface.This work provides a new perspective on the anti-icing system in the real-world environments.
基金supported by the Research Funding of Hangzhou International Innovation Institute of Beihang University(No.2024KQ130)the National Natural Science Foundation of China(No.52373259).
文摘In order to alleviate the growing problem of electromagnetic radiation pollution,it is both urgent and challenging to develop electromagnetic wave absorbing materials with strong absorption and wide effective absorption bandwidth(EAB).The structural design of heterojunction surfaces plays an important role in the development of advanced microwave absorbing materials.Building on this concept,three-dimensional nanocomposites Alk-Ti_(3)C_(2)T_(x)/nitro metal phthalocyanine(TNMP)with phthalocyanine derivative NMP-MXene are designed.TNMP composites are prepared by self-assembly of surface hydroxylated treated MXene with floral spherical nitrophthalocyanine.This method effectively constructs rich heterojunction surfaces and induces dipole polarization effect by designing a large number of oxygen vacancies through coordination,which effectively enhances the material attenuation capability while balancing impedance matching characteristics.By modulating the metal centers in the NMP,the coordination mode of the heterojunction surfaces is regulated,and the polarization relaxation loss is improved to achieve excellent electromagnetic wave absorption performance(reflection loss(RL)of-62.12 dB at a thickness of 1.25 mm).And based on the bionic structure design,a unit cycle structure of double-layered butterfly wing skeleton(DLBWS)is constructed to obtain an ultra-wideband electromagnetic wave absorber with an EAB of 12.5 GHz.This research demonstrates a regulatory scheme to elucidate the dipole polarization mechanism and proposes a new method for designing functional materials in ultra-broadband electromagnetic wave absorption.
基金supported by the Fundamental Research Funds for the Central Universities(No.2024KQ130)the National Natural Science Foundation of China(No.52373259).
文摘The design and fabrication of efficient microwave absorbing materials with tunable wave attenuation capacity to address the increasing demand for electromagnetic pollution mitigators remains a challenging task.In this study,Ag_(2)Te and a series of Ag/Ag_(2)Te composites have been successfully synthesized by using a facile one-step solvothermal method through varying the molar ratio of the reactants and reaction time.To investigate the microwave absorption performance of these composites,the samples are mixed with polyvinylidene difluoride matrix under different filler ratios.The experimental results indicate that the AT3(where the molar ratio of Ag:Te is 4:1)sample possesses optimal wave dissipation ability with a minimum reflection loss value of−55.98 dB at 15.01 GHz and a maximum effective absorption bandwidth of 4.90 GHz(13.10-18.00 GHz)at a thickness of 1.7 mm when the filler content is 10 wt.%.Moreover,the widest EAB of 6.20 GHz(10.60-16.80 GHz)is recorded in the Ag_(2)Te sample.Meanwhile,it is observed the solvothermal reaction time can effectually influence effective wave absorption frequency.As the reaction time increases,the position of the minimum reflection loss(RLmin)shifts to lower frequencies.The analysis of the wave absorption mechanism demonstrates that the novel crooked one-dimensional linear structure and abundant heterogeneity within the Ag/Ag_(2)Te composite plays an important role in achieving outstanding wave absorption performance.The specific wave absorption mechanism includes conductive loss,multiple scattering,multiple resonant coupling,interface polarization and electric dipole polarization.This work can provide an effective strategy for the design of high-performance MAMs through constituent and morphology modulation.
基金supported by the National Natural Science Foundation of China(52303143,22175011,52472293)China Postdoctoral Science Foundation(2021TQ0023,2022TQ0022,2022M720012)+5 种基金National Key R&D Program of China(2019YFB1309702)Beijing Young Talent Support ProgramTianmushan Laboratory Research Project(TK2023C018)Beijing Nova Program(20220484213)Key Laboratory of Icing and Anti/De-icing of China Aerodynamics Research and Development Center(IADL20230401)Fundamental Research Funds for the Central Universities。
文摘Traditional cloth diapers are fully reliant on the water retention capacity of the absorbent cores to deter leaks,often overlooking the role of the top sheet,which can lead to reverse osmosis of absorbed urine.Janus membranes,known for their liquid diode effect,present an ideal material for the top sheet of cloth diapers.However,the widespread application of Janus membranes in cloth diapers faces challenges such as failure to meet anti-backflow requirements,limited biocompatibility,and insufficient antimicrobial properties.Here,a multifunctional Janus fabric for the top sheet of cloth diapers is developed through the synergistic combination of gradient wettability and nanoparticle functionality.The modulable gradient wettability provides unidirectional liquid transport with a high rectification ratio,which is essential for preventing liquid backflow.Consequently,prototype cloth diapers incorporating Janus fabrics as the top sheet outperform commercial products in wetback resistance.Functionalized silver nanoparticles not only provide the necessary micro-nano hierarchical structure for gradient wettability but also endow Janus fabrics with excellent chemical antibacterial properties.The integration of dryness derived from the excellent unidirectional transport performance and antibacterial properties effectively prevents bacterial growth on cloth diapers.Additionally,the Janus fabrics exhibit excellent washability and biocompatibility,further enhancing their potential applications in reusable cloth diapers.
